3. If a couple is monogamous for 20 what’s the most likely explanation if one of them receives a new HPV diagnosis?  Is infidelity by one partner likely? If one partner was a virgin before the relationship began, would that change your assessment?

I agree you are "missing something". These questions seem to reflect a couple of misunderstandings. First, there are over 100 types of HPV, of which 30-40 regularly are sexually transmitted. The vaccines cover 9 types (Gardasil 9, the only one available in the US) or just 4 types. These are the HPV types that cause around 90% of serious outcomes, i.e. cancers and genital warts. Second, in most geographic areas, not enough people have been vaccinated. The frequency of abnormal Pap smears cervical cancer is decreasing in the US, however. And genital warts and pre-cancer problems due to HPV are becoming uncommon in countries where vaccination programs have been more successful, such as Australia and Scandinavian countries. Third, the vaccines do nothing for HPV infections acquired before receiving the vaccine.

1. Why does HPV remain so common? Because not enough people have been vaccinated, and because of all the HPV types not prevented by the vaccines.

2. This question assumes that most sex workers have been vaccinated; and, equally important, that they were vaccinated before becoming infected with some of the HPV types the vaccine prevents. This definitely is not the case. In any case, sex workers are no more common sources of HPV infection than non-sex-worker partners.

3. Sometimes two persons who never had sex with anyone else come together and remain mutually monogamous for life, but it's pretty uncommon overall. If either partner has had other partners, that's by far the main explanation for a newly diagnosed HPV infection -- i.e. reactivation of an HPV infection acquired in the distant past. This explains most abnormal Pap smears in women over age 30 or thereabouts. However, some HPV infections have mysterious origins, apparently acquired by nonsexual routes; once in a while infection is diagnosed in someone who truly was never at sexual risk. 

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

Dr. Handsfield: Thanks for this response. I greatly appreciate how you take every question seriously, and offer real assurances.

I do have a follow up question.  Are you aware of information relating to how long an HPV infection might lay dormant? Is it really possible for HPV to appear decades after it was acquired either as warts or in a pap test?  I am thinking particularly about my hypothetical regarding a monogamous couple. If one partner entered the relationship as a virgin and the other had some sexual experience before the relationship--but never had any symptom of HPV--is it really likely that the virus would lay dormant in one or both partners for decades? Or is it more likely that the appearance of the virus indicates that one of the partners was unfaithful during the relationship and it was a new infection?

Is there someplace to learn more about the mysterious and non-sexual causes of HPV?  I am fascinated about all the discussion and fear relating to HPV online when apparently it's sometimes not even actually an STI? Is that right?

Thanks again.

"Is it really possible for HPV to appear decades after it was acquired either as warts or in a pap test?" This happens all the time. It accounts for most abnormal Pap smeears in women over 30 years of age.

"If one partner...one or both partners for decades?" Yes indeed.

"Or is it more likely...a new infection?" Of course this can happen. But in and of itself, a new HPV diagnosis never is sufficient evidence to assume infidelity on the part of either partner.